The invention relates to tissue collection devices such as blood collection devices that comprise biosensors for the detection of target analytes such as nucleic acids and proteins, including antibodies and enzymes.
The areas of molecular pathology, molecular oncology and molecular diagnostics are rapidly expanding, with the development and validation of new molecular techniques of paramount importance in the clinical setting. With the rapidly accelerating pace of discovery of new disease genes and a growing awareness of the role of genetic components of many disease states, the need for rapid, inexpensive and accurate tests is growing exponentially.
Generally, these tests can be classified into several categories, including nucleic acid tests (for pathogens, oncogenes, genetic diseases, etc.) and immunoassay tests (for a wide variety of antigens and antibodies). In addition, the growing knowledge regarding causative mutations in human genes and single nucleotide polymorphisms (SNPs) leads to the need and desire to test the population to diagnose and identify those at risk for these genetic diseases.
Clinically, these tests require a patient sample, frequently blood, into a tissue collection device, such as those described in U.S. Pat. Nos. 4,991,104, 3,974,930, 4,301,936, 4,187,952, 4,186,840, 4,136,794, 4,465,200, 4,111,326, 6,001,087, 6,001,429, 5,975,343 and 5,968,620. The sample is then generally processed, using a variety of steps, and the assay run.
Simultaneously, the area of biosensors is rapidly expanding. Many of these rely on specific ligand/antiligand reactions as the mechanism of detection. That is, pairs of substances (i.e. the binding pairs or ligand/antiligands) are known to bind to each other, while binding little or not at all to other substances. This has been the focus of a number of techniques that utilize these binding pairs for the detection of the complexes. These generally are done by labeling one component of the complex in some way, so as to make the entire complex detectable, using, for example, radioisotopes, fluorescent and other optically active molecules, enzymes, etc.
Other assays rely on electronic signals for detection. A number of systems have been described; see U.S. Pat. Nos. 5,591,578; 5,824,473; 5,770,369; 5,705,348; 5,780,234; and 5,952,172; WO98/20162; WO99/37819; PCT US98/12430, PCT US99/01703; PCT US98/12082; PCT/US99/14191; PCT/US99/21683; PCT/US99/25464 and PCT US99/10104; and U.S. Ser. Nos. 09/135,183; 09/295,691 and 09/306,653.
In general, it would be desirable to provide the ability to test a tissue sample with a minimum of handling steps. It is an object of the invention to provide tissue collection devices that have incorporated biosensors, particularly electrodes, for use in diagnosis and screening.
In accordance with the above objects, the present invention provides tissue collection devices, particularly blood collection devices, comprising an electrode. The electrodes may further comprise self-assembled monolayers and capture binding ligands, particularly nucleic acid capture probes. The monolayers may comprise insulators and/or electroconduit-forming species (EFS). The devices may further comprise at least one reagent, including anticoagulants, probe nucleic acids, and lysis reagents.
In a further aspect, the invention provides method of detecting a target analyte is a sample comprising applying an initiation signal to a tissue collection device comprising an electrode. The electrode may comprise a self-assembled monolayer and an assay complex comprising a capture binding ligand, the target analyte and an electron transfer moiety. The methods further comprise detecting electron transfer between the electrode and the electron transfer moiety. The methods may further comprising collecting the sample, for example using blood collection equipment.